Surface hydraulic fracturing is a new technology for preventing rockburst in deep mines with hard and thickness roofs in the Nei Monggol and Shanxi mining area. Determining the target rock layer for surface fracturing is a key issue for the success of this technology. Based on the positional relationship between the hard and thick roof strata and the caving zone in the working face, two types of bearing structures are proposed, and corresponding bearing mechanical models for the hard-thick roof are set up.The calculation methods for the fractured step distance,roof fracturing energy and its transmission of the hard and thick roof are given. Further the mechanical failure criterion of rock burst in coal roadway caused by roof fracture is provided. Combined with practices of surface hydraulic fracturing for rockburst prevention in the Binchang and Dahaize mining area and so on, the method of identifying target rock layer for surface hydraulic fracturing is proposed based on the fracturability of the target rock layer, the disaster potential of energy transfer, and the position of the rock layer. The method was adopted to obtain the target stratum for the surface fracturing and ground pressure relief at the 401102 working face of Mengcun Coal Mine. The results showed that: The target stratum for surface fracturing at the 401102 working face of Mengcun Coal Mine are the coarse sandstone layers at 65.95 m and 99.31 m away from the coal seam, respectively. The target stratum of the 401102 working face were fractured by the surface fracturing wells. The periodic fractured step distance, ground pressure duration, ground pressure intensity, total microseismic frequency and total released energy in the working face and coal roadway in hydraulic fracturing area all are significantly reduced, and the surface fracturing has good effect. The method for determining the target stratum proposed in this paper is reasonable, and the paper provides calculation method to determine the target rock layer for surface fracturing.

In view of the problems faced by the application of surface hydraulic fracturing technology in the field of coal mine roof weakening, such as shallow burial depth, complex formation stress, structural development, coal seam fluctuation and adjacent goaf, the key technology and engineering application research of surface hydraulic fracturing technology for weakening thick and hard roof of coal seam were carried out. The results show that: from the perspective of rock structure transformation, the prefabricated joint network destroys the local rock layer, thus reducing the bearing capacity of rock structure; From the point of view of physical property modification, the radiation effect of fracturing injection pressure and elimination of local stress concentration area in the rock layer make the rock layer tend to stress homogeneous state. A fracture target layer identification method based on theoretical calculation and open hole logging measurement is proposed. Based on the formation description and floating collar tool, the high-precision trajectory control and high water sag ratio casing running technology are improved. The directional perforation, efficient temporary plugging and steering technology of fracture network are introduced to realize the direction and scale control of fracture network near the wellbore, and the well ground data fusion analysis method during fracture network dynamic monitoring and recovery is constructed. The engineering practice and application of multi-objective layer vertical wells and shallow buried horizontal wells with large water vertical ratio were carried out respectively to achieve the technical objectives of multi-objective layer dynamic optimization, unilateral temporary plugging and steering of fracture network, accurate control of drilling trajectory between coal seams, casing completion with 2.82 water vertical ratio, fracture network direction and scale control, and formed the ground fracturing weakening technology system of thick and hard roof in coal mine.

Aiming at the high risk of rock burst in the longwall faces along the goaf in the Hetaoyu Coal Mine, which has a kilometer-depth burial, extra-thick coal seam, and thick hard roof, research and application of the hydraulic unloading technology system for the low, middle, and high roof of the working face have been carried out. The results show that the rock burst in the goaf roadway is affected by the superposition of the overhanging roof in the goaf, the mining stress of the working face itself, and the high roof fracture dynamic load after double-sided mining. Combined with the mine conditions, a local + regional hydraulic roof unloading technology system was proposed, using abrasive waterjet for lateral roof cutting, underground long-hole segmented hydraulic fracturing, and high roof ground regional fracturing measures to achieve roof cutting on the side of the working face along the goaf, roof breaking in the strike direction, and regional weakening of the high roof. The engineering practice of hydraulic roof unloading technology was carried out in the 2803 working face. Through borehole peeping, transient electromagnetic detection, and micro seismic monitoring and analysis, the prevention and control effect of hydraulic roof unloading technology is significant. Compared with the adjacent solid coal working face without hydraulic unloading measures, the micro seismic energy release and the on-site dynamic manifestation have been significantly reduced, forming a hydraulic unloading technology system for thick and hard roof in the working face along the goaf in Hetaoyu Coal Mine.

To address the challenges of deep-hole roof-cutting blasting technology for weakening thick hard roof strata to prevent rock bursts—such as high engineering workload, limited pressure relief range, and elevated risks—this study focuses on the 20101 first mining face of Dahaize Coal Mine as the engineering case. Utilizing theoretical analysis and field measurements, the research investigates the mechanism of ground hydraulic fracturing for rock burst prevention, identifies optimal target strata, evaluates fracturing effectiveness, and analyzes the application. Key conclusions are as follows:① Hydraulic fracturing generates fracture networks in thick hard roof strata, compromising their integrity, releasing elastic energy in advance, redistributing high stress, reducing fracture length LL, and lowering dynamic loads.② Analysis of fracturing curves, water discharge from roof boreholes in the working face, and microseismic monitoring data confirms that fracturing fluid induces fractures in target strata. The fracture network extends 255.1 m along the strike direction, 72.0 m along the dip direction, and 61.9 m vertically.③ Compared to non-fractured conditions, post-fracturing results show reductions in total microseismic event frequency and energy by 58.95% and 67.84%, respectively. Periodic weighting intervals and dynamic load coefficients decreased by 6.3% and 10.8%, while roof collapse intensity remained stable.The findings demonstrate that ground hydraulic fracturing effectively weakens roof strata, significantly reduces rock burst risks in working faces, and achieves pressure relief in thick hard roof zones. This provides a reference for rock burst prevention in deep mining faces of the Yuheng Mining Area.

Aiming at the problem of dynamic disaster caused by the fracture of thick and hard roof in the mining process, taking the 11-3107 working face of Menkeqing Coal Mine as the engineering background, the layout method of fracturing horizontal drilling in thick and hard roof area is deeply explored by means of theoretical analysis, numerical simulation and field practice. Firstly, through the multi-dimensional analysis of roof lithology analysis, key layer discrimination, energy transfer research and microseismic monitoring, it is determined that there are key layers I, II and III in the overlying strata of 3107 working face, and their breaking has high energy transfer to coal body. It is comprehensively determined that the middle and low positions of 15-30 m and the middle and high positions of 45-60 m are fracturing horizons and need dynamic adjustment. Secondly, the numerical simulation is used to analyze the water injection leakage in different mining failure ranges, and the horizontal borehole layout parameters are determined, and the pre-splitting effect of roof blasting is evaluated. Based on the above research, the regional fracturing scheme of 3107 working face is put forward, which provides a solid technical support for the subsequent safe and efficient mining of 3107 working face in Menkeqing Coal Mine.

In order to further explore the influence of ground fracturing measures on the impact risk of gob-side working face and the anti-impact mechanism. Taking the 20103 working face of a mine in Shaanxi Province as the engineering background, the anti-impact mechanism and its control effect of ground fracturing measures between two adjacent working faces to reduce the impact risk during the mining of the upper working face and the lower working face were studied by means of theoretical analysis and field detection. The following conclusions are drawn : the implementation of ground fracturing measures between two adjacent working faces can reduce the mechanical properties of the rock strata as a unified whole before the mining of the upper working face, thus reducing the overall static load below the fracturing area. When mining in the lower working face, the surrounding rock of the roadway along the goaf is in a relatively low static load stress environment, and because of the decrease of the length of the lateral cantilever after the implementation of ground fracturing, the dynamic load energy from the fault zone is greatly reduced, and the impact risk caused by the superposition of dynamic and static loads is significantly reduced. In the actual lateral hanging roof detection process, the lateral cantilever structure of the fractured area and the unfractured area is obtained. The comparison results show that the ground fracturing effect is good, the weakening degree of the lateral cantilever is high, and the long arm is effectively realized. The implementation of ground fracturing has a good effect on reducing the impact risk of the working face along the goaf, which can provide reference for the prevention and control of rock burst in the working face along the goaf of the same type of mine.

Aiming at the problem of intense ground pressure manifestations caused by large-scale fracture instability of hard roof strata above coal seams in the Mengshan-Shaanxi deep mining area—which may induce rockburst under severe conditions—this study takes the 2202 working face of Balasu Coal Mine as its engineering context. Through theoretical analysis and field measurements, the research investigates the mechanism and application of ground hydraulic fracturing for weakening thick-hard roof strata and preventing rockburst in deep mines of this region. The conclusions are as follows:① Hydraulic fracturing creates fracture networks within thick-hard strata, weakening their physical and mechanical properties. This reduces fractured block sizes, diminishes energy accumulation capacity in thick-hard strata, and lowers dynamic loading during fracture. Simultaneously, it enhances energy dissipation, reducing the impact of dynamic loading from overlying fractured layers on stress distribution in underlying coal seams.② The target fracturing horizon and key parameters were determined based on comprehensive considerations: avoiding compromise to existing roadway support structures while effectively weakening energy accumulation capacity in thick-hard strata.③ During hydraulic fracturing, pressure-flow-time curves and water discharge from underground drainage boreholes demonstrate successful fracture generation in thick hard strata, confirming effective fracturing. Post-fracturing data show significant reductions in: total energy and frequency of microseismic events; frequency of high-energy events (>5,000 J); average periodic weighting interval; and average dynamic loading coefficient.The results demonstrate that hydraulic fracturing can substantially mitigate ground pressure manifestations at working faces, offering valuable insights for rockburst prevention in mines with similar geological conditions across the mining area.

Thick and hard roofs is a key factor inducing coal burst in coal mining, and the use of overlength horizontal hole staged fracturing technology to decompress the thick and hard roofs has become an effective means to prevent and control coal burst. In order to analyse the effect of overlength horizontal hole staged fracturing on the prevention and control of thick and hard roofs-type coal burst, the 11-3107 working face of coal mine in Ordos was taken as the research object, and microseismic monitoring, support working resistance monitoring and surface subsidence monitoring means were comprehensively used to carry out the analysis. The results show that overlength horizontal hole staged fracturing has a significant effect of unloading energy and weakening load shedding. The microseismic energy, frequency and supporting pressure of the working face after the implementation of overlength horizontal hole staged fracturing for thick and hard roofs were greatly reduced, and the surface subsidence was on the trend of increasing, with the average daily microseismic energy and frequency being reduced by 1.1×105J and 27, or about 67.50% and 33.75%, respectively, and the supporting pressure being reduced by 21.5%, and the surface subsidence being increased by about 87.59%. The integrity of the roof is weakened and its strength is reduced after the implementation of overlength horizontal hole staged fracturing for thick and hard roofs, so that it can be broken and collapsed in time after coal mining, and it is not easy for energy to accumulate in the roof, and the overhanging area is reduced, which reduces the dynamic load during the mining period, and then reduces the risk of coal burst induced by the breaking of the thick and hard roofs. The overlength horizontal hole staged fracturing has a positive effect on reducing the risk of thick and hard roofs-type coal burst, and the results of the study can provide a reference for the prevention and control of thick and hard roofs-type coal burst．

The study investigates the temporal and spatial evolution patterns of hydraulic fractures in rock during the hydraulic fracturing process for roof stress relief in coal mines. By employing the discrete element method, a model for hydraulic fracture propagation and particle displacement was constructed to analyze the responses of fracture quantity and morphology, particle displacement, and damage zone area to variations in water pressure, cohesion, porosity, and Young's modulus. The results show that an increase in water pressure causes the fractures to transition from linear to complex mesh or branched forms, providing more channels for particle displacement and increasing the damage zone area. However, excessive water pressure may induce compaction effects, reducing the effectiveness of fracture channels and inhibiting further damage zone expansion. An increase in cohesion makes fracture propagation more regular, with particle displacement transitioning from disordered to ordered. Porosity influences the complexity of fracture propagation and the amplitude of particle displacement, while an increase in Young's modulus results in more concentrated fracture paths and enhanced directional particle displacement. The temporal evolution of fractures can be divided into the initiation stage, micro-crack propagation stage, and rapid crack propagation stage. The temporal evolution curves of hydraulic fractures under different variables follow an exponential distribution. This study provides a theoretical basis for optimizing hydraulic fracturing construction processes and offers guidance for improving roof stress relief efficiency.

To enhance pressure relief and permeability in deep, high-gas coal seams, this paper proposes a surface well cavity creation and pressure relief permeability enhancement technique. A multi-field coupling model of gas migration in the reinforced coal body of the cavity creation area was constructed, analyzing the influence of different parameters on the area of the damaged coal body, permeability, and gas pressure. Simulation based on the coal excavation and cavity creation at the Zhangji Mine A group site analyzed the pressure relief and permeability enhancement effects under different initial permeability and extraction time conditions. The study indicates that reducing borehole spacing promotes connectivity in the damaged area, but excessively small spacing is detrimental to permeability improvement. Increasing borehole size significantly enlarges the damaged area and permeability. The smaller the cohesion of the coal body, the more notable the permeability enhancement effect. With an increase in the internal friction angle, both the damaged area and permeability decrease. Additionally, low initial permeability results in a reduced effective extraction radius. Investigations of underground gas parameters show that after implementing the surface drilling large-diameter coal excavation and cavity creation process, gas pressure and content significantly decrease, the permeability coefficient increases by approximately tenfold, effectively improving gas extraction efficiency.

Rockburst disaster caused by the superimposed action of strong dynamic load and high concentrated static load formed by mining in the mining process of working face with complex geological conditions and mining conditions. This paper takes the 7302 irregular working face of Zhaolou Coal Mine as the research object, through on-site sampling test, impact risk assessment, theoretical analysis, refined numerical simulation, multi-parameter monitoring and warning, and prevention and control collaborative control technology, etc, The mechanism and prevention of mining induced impact of irregular working faces in the area affected by complex fault structures are studied. The results show that the shear modulus of the weak plane of the fault is in direct proportion to the shear stress required for sliding instability. When the consistency of the failure strength of the bond point on the weak plane of the fault is high, it will produce an instantaneous stress drop in the state of stick-slip friction and induce a strong mine earthquake; When the the working face width is large, the thick and hard layer in the middle and high level of the overburden is more likely to reach the limit breaking distance and break, resulting in strong dynamic load disturbance, at the same time, the static load stress concentration and range in the surrounding rock of the mining space are increased; The refined three-dimensional numerical simulation has determined the potential impact risk area, and pointed out that the mining has disturbed the Fz14 reverse fault and Fd64 normal fault, which led to its activation; Multi-parameter spatial quantitative technology can identify and monitor precursors during mining in real time, and can timely feedback the effectiveness of prevention and control collaborative control technology

In order to solve the problem of process selection for underground on-site deep treatment and reuse of complex mine water with high hardness, high mineralization and iron and manganese exceeding the standard, this study proposed the treatment process consisting of “aeration oxidation + flocculation and sedimentation + multi-media filtration + manganese sand filtration + reverse osmosis”, which had a short process chain, good treatment effect, and stable effluent water quality. Through the pilot test to verify the treatment effect of the optimization and adjustment process, the system consistently produced water with turbidity below 0.5 NTU, iron and manganese below 0.1 mg/L, residual chlorine below 0.1 mg/L, and conductivity below 60 μS/cm, meeting the water quality requirements for underground production equipment. The reverse osmosis recovery rate stabilized at 50%. The study provided valuable guidance for the process selection in the design of on-site treatment and reuse systems for complex mine water with high hardness and high mineralization in underground arrangement.

This study aims to address the issues of high energy consumption and the difficulty in dynamically adjusting equipment parameters in the operation of water systems in refrigeration plants. A modeling and optimization method driven by measured data is proposed. First, the TRNSYS software is used to build an operational model of the refrigeration plant’s water system, incorporating key equipment such as screw-type chillers, chilled water pumps, cooling towers, and the piping network. Then, the TRNSYS model is calibrated and adjusted using experimentally measured flow data from the chilled water system of a coal mine refrigeration plant, ensuring that the simulation accurately reflects real operating conditions. Next, the Particle Swarm Optimization (PSO) algorithm is employed to iteratively search and optimize key operational parameters of the system—including chilled water supply temperature, the number of operating chilled water pumps, and pump speed ratios—with the goal of minimizing energy consumption and optimizing system efficiency. The results show that after applying the PSO algorithm, the overall energy consumption of the system across different load ranges was reduced by an average of 13.97%, demonstrating the effectiveness of the proposed method. The conclusion indicates that this method not only significantly reduces the operational energy consumption of the refrigeration plant’s water system and enhances system efficiency, but also provides a feasible technical approach for energy efficiency optimization of similar systems, holding great significance for energy conservation, emission reduction, and sustainable development．

The Cretaceous system in the Ordos Basin exhibits characteristics such as high-water content, clay-bearing layers, and weak cementation, which have significant engineering and environmental effects, posing notable geological challenges for shaft construction. An analysis of the issues encountered during shaft sinking in Ordos Basin reveals that the ratio between frozen wall thickness and maximum shaft radius in Cretaceous strata often deviates by more than 50%. There is also a notable discrepancy between actual water inflow observed during excavation and the predicted amounts, complicating the control of key sinking parameters such as freezing, grouting, and open excavation. Traditional methods were proving inadequate, grouting was ineffective, and freezing methods carried significant risks. The challenges in shaft sinking are exacerbated by tectonic stress from the Yanshanian and Himalayan orogenic periods, which, combined with the heterogeneity of the strata, have led to the development of two major sets of regional structural fractures. These fractures exhibit early-stage uneven compression followed by asymmetric shearing, giving rise to compressive torsion characteristics. These structural fractures, located in the surrounding strata of the shafts, differ from larger faults and microcracks. Their scale, comparable to the diameter of the shafts, leads to complex, nonlinear interactions between groundwater, sandstone, fractures, and the shafts. These interactions can result in severe consequences, such as lining failure and shaft flooding. To address these issues, a compressive torsion fracture CT visualization system and a method for preparing water-rich, clay-bearing, weakly cemented sandstone have been developed. The goal is to reveal the characteristics, formation processes, and evolution of compressive torsion fractures, as well as the mechanisms of disaster caused by disturbances to these fractures. These researches will help establish precise, in-situ monitoring methods and lead to the development of a lining load model that accounts for the coupled effects of groundwater, sandstone, fractures, and shafts. Ultimately, it will support the innovative development of disaster prevention theories for shaft linings and provide the scientific basis needed to solve the geological challenges hindering shaft construction and operation in Western China.

The stress environment of coal mining can be effectively improved by hydraulic fracturing technology. Studying the stress-induced microscopic cracking and expansion patterns of hydraulic fracture is essential for advancing the theory of fracturing control and optimizing the selection of fracturing locations. Using MatDEM software, hydraulic fracturing simulation tests were conducted under two different conditions: constant confining stress and stress difference. The results indicate that: (1) Hydraulic fractures under constant confining pressure were distributed at 120° due to the uneven distribution of particles around the borehole wall and the priority expansion of unilateral fracture. In the presence of stress difference, the main fracture was straight and single. The compressive stress concentration area distributed at both ends of the fracture is negatively correlated with the stress difference, and a tensile stress fracture mode is visible at the tip. (2) The curve of pumping pressure growth rate initially sharply increases and then gradually stabilizes, indicating hydraulic fracture penetration. This pattern is consistent with the fluctuation characteristics of the cumulative increase velocity of micro-cracks. According to the above indexes, the fracturing process can be divided into four stages: no micro-cracks, slow growth of micro-cracks, steady growth of micro-cracks, and rapid growth of micro-cracks. (3) High confining pressure promotes the initiation of fractures and inhibits the development of the fracture process zone. A high stress difference enhances the control of fracture initiation and propagation, which is reflected in the connection and closure of branch cracks. (4) To ensure that the hydraulic fracture meets the requirements of the working conditions, the fracturing area is selected based on the minimum horizontal principal stress and stress difference. This approach allows for better control over both the main fracture and branch fractures, and helps to mitigate any potential adverse effects caused by stress disturbance during fracturing operations, particularly in areas with high stress differences.

In order to solve the problems of resource utilization of coal-based solid wastes such as coal gangue and reducing carbon emissions, a new type of filling and grouting material was prepared by partially replacing cement with calcined coal gangue powder and fly ash as raw materials and mixing nano silica. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to analyze the composition and microstructure of the raw materials. Combined with the Box-Behnken experimental design, the influence of each component on the compressive strength and fluidity of the slurry was determined, and the optimal mix ratio was obtained, and a new damage constitutive model was established, which can fully describe the stress-strain curve and provide a reference for the application of engineering practice. The test results show that the order of influence of each key factor on the fluidity of grouting materials is as follows: B (fly ash substitution rate), > A (calcined coal gangue powder substitution rate), > C (nano SiO2 addition rate). The order of influence on compressive strength is as follows: B (fly ash substitution rate), > C (nano SiO2 addition rate), > A (calcined coal gangue powder substitution rate). The optimal ratio of each factor was as follows: the substitution rate of calcined coal gangue powder cement was 21.16%, the substitution rate of fly ash cement was 30.3%, and the addition rate of nano SiO2 was 0.511%.

In order to quantitatively analyze the development of overburden fractures in the roadway along the headway for pressure relief at the cutting top, so as to determine the reasonable height of the cutting top, a quantitative statistical analysis method based on Avizo software was proposed. Based on the engineering background of 8104 return air roadway retaining along the headway in Nianyan Coal Mine, theoretical analysis, numerical simulation and field industrial tests are used to study the overlying rock migration law and fracture development of the retaining under the condition of no cutting and different cutting height based on Avizo software, The mining pressure development law and its effect of cutting roof relief along the headway retaining are also analyzed, The results show that: (1) The height of caving zone increases with the height of cutting top, and the height of fracture zone is the same as that without cutting top.(2) Under the condition of roof cutting, roof fissure area and gob gangue compacting void area decrease exponentially with the increase of roof cutting height. When the top cutting height is 12 m, the top cutting effect is the best. Compared with no roof cutting, roof fissure area and gob gangue compacting void area decrease by 74.3% and 38.4%, respectively. (3) The displacement of top and floor and the displacement of two sides along the goaf retaining roadway show three significant characteristics: slow deformation, rapid deformation and deformation tends to be stable. The displacement of top and floor and the displacement of two sides stabilize within 400 mm after the delayed working face is 300 m, which ensures the safe and efficient production of the mine.

Abstract: The conventional method for positioning coal mining machines predominantly depends on the inertial navigation system. In the challenging operating conditions of a fully mechanized mining face, the positioning system is susceptible to cumulative errors, leading to a progressive decline in accuracy. Additionally, the coal mining machine occasionally encounters irregular driving events, such as slippage, causing anomalies in odometer readings. To address this issue, this paper presents an integrated positioning approach utilizing robust cubature Kalman filtering. By loosely coupling the SINS and OD systems, the speed and displacement data from the odometer are merged with the inertial navigation system’s solution results and incorporated into the filtering algorithm as error observations. Simultaneously, a robust processing method based on the chi-square test of innovation is introduced into the filtering algorithm. Through the construction of a variance inflation factor and adjustment of the observation covariance matrix, it influences the cubature Kalman filtering procedure to achieve robust filtering. The filtered output is fed back into the system as error correction to enable feedback adjustments, and the effectiveness of the combined state is evaluated once the entire solution process is finalized. Simulation and experimental results show that the algorithm can effectively reduce the influence of gross errors, and the positioning accuracy can reach 0.1m after using the integrated navigation algorithm.

Underground coal mine auxiliary operation robot equipment can reduce labour intensity, improve safety production efficiency, by more and more researchers' attention, three-dimensional scene real-time perception and spatial target detection and positioning is the basis of accurate control and autonomous operation of underground auxiliary operation robot. The research is centred on target detection and control system for underground assisted operation robots in coal mines, firstly, it studies the fusion analysis method based on 3D LiDAR and video image data, and realises the spatial and temporal synchronization of laser point cloud data and image data, as well as the matching analysis of the position. Then, the improved YOLOv8s image target detection algorithm model based on Slim-neck feature fusion network and the 3D point cloud target detection algorithm model based on PointPillars are designed, which reduces the complexity of the model while maintaining the recognition accuracy, on the basis of which, the improved DS evidence theory based on the Lange's distance is proposed, and the fusion target detection model YOPilaNet for the video image and 3D point cloud data is established. Experimental validation is carried out using the KITTI dataset, and the experimental results show that the proposed YOPilaNet fusion model significantly outperforms the target detection performance under single modal data. Finally, combining the embedded GPU processor and real-time operating system, a cooperative control system for target detection and multi-axis robotic arm is designed for underground coal mine robots, which can meet the demand for efficient automated operation in underground handling, pipeline assistance and other application scenarios.

The intelligent mining sector suffers from a lack of big data support, and the application of foundational AI platforms and algorithms is limited. The main reason is the absence of an industrial internet architecture cloud platform tailored for the coal industry, which restricts resource integration. This leads to high failure rates of equipment on comprehensive mining workfaces, along with high maintenance and labor costs. By integrating cloud-native technology, edge computing, big data platforms, and artificial intelligence platforms, a flexible, modular industrial internet architecture remote maintenance platform has been developed to meet these challenges. The platform employs graph and document large model technologies and uses the Bert-BiLSTM-CRF model for knowledge extraction and knowledge graph construction, significantly improving the accuracy of knowledge extraction. The successful development of the platform has narrowed the gap with other energy sectors' industrial internet applications and laid a foundation for the realization of intelligent and unmanned coal mining in the coal industry.

In order to enhance the comprehensive utilisation rate of mine water and alleviate the problem of high cost of mine water treatment and purification, this paper is predicated on the concept of an ‘underground water reservoir’, focusing our research on the purification and adsorption effects of collapsed coal rock accumulations in goaf areas on mine water. Three groups of coal particles with varying particle sizes were selected for use in the filtration device. The suspended mine water, containing different concentrations of gangue powder, was imported for analysis. This was conducted in order to evaluate the impact of collapsed coal rock piles on the suspended matter of the mine water, under conditions of different filling particle sizes, flow rates, times and circulation distances. The results show: it was determined that the filler with a smaller particle size exhibited a superior adsorption effect on the suspended matter in mine water. Additionally, the lower flow rate, longer transport distance and prolonged filtration period were observed to have a more pronounced adsorption effect on the suspended matter. On the basis of theoretical research, 15102 workface of Shanxi Lingzhida Coal Mine was selected as the object of engineering practice. It was found that the collapsed coal rock accumulations in the mining area had a beneficial filtration and purification effect on mine water. The results can provide a good theoretical basis for underground treatment of mine water and serve as an engineering demonstration.

Aiming at the problem of accurately predicting the ash content of tailings in the flotation process to achieve automatic control, a prediction method for the ash content of flotation tailings based on near-infrared image analysis was proposed based on near-infrared spectroscopy and image processing technology. A hybrid intelligent detection model for the ash content of flotation tailings was constructed by combining polynomial regression (PR) for preliminary prediction and random forest (RF) for compensation prediction. Twelve feature data including gray level and texture were extracted from the gray histogram and gray-level co-occurrence matrix of tailings images. After feature selection, a linear prediction model was established using PR, with a root mean square error (RMSE) of 2.752 and a coefficient of determination (R2) of 0.977. To improve the prediction effect, an RF compensation model was introduced on the basis of PR. The selected gray level and texture feature data were used as input, and the difference between the preliminary prediction value and the actual value was used as output. Finally, the preliminary prediction value and the compensation prediction value were added to obtain the ash content of flotation tailings, and a prediction model for the ash content of flotation tailings based on RF-PR hybrid was established. This model has high accuracy: in the low ash content range (11.1%-21.3%) and high ash content range (68.9%-76.2%), the difference between the preliminary prediction value and the offline laboratory value of tailings is reduced; in the medium ash content range (21.3%-68.9%), the mean absolute error (MAE) of the preliminary prediction value is reduced by 0.07. The results show that the RF-PR model has higher accuracy than the PR model and the RF model, and can meet the requirements of ash content detection of flotation tailings.

The pore structure of the filter cake plays a crucial role in the filtration efficiency. However, the existing three-dimensional characterization techniques are faced with high testing costs, which limits the in-depth understanding of the dynamic dewatering mechanism. This paper conducts a study on the three-dimensional reconstruction technology of the pore morphology of industrial coal sludge filter cakes by using ImageJ software in combination with multi-point sampling of the filter cake and scanning electron microscope examination (SEM). In addition, by cutting the three-dimensional reconstructed filter cake slices and using the Dijkstra algorithm for path analysis, the porosity gradient (20.0 - 43.6%), ineffective pores (2.19 - 9.49%), and tortuosity (1.64 - 2.05%) at the micrometer scale resolution were quantified. The results show that coarse particle settling increases the bottom porosity, while fine particles near the feed inlet increase the ineffective pores, resulting in a 30.6% reduction in effective permeability. This method establishes a spatial connection between the heterogeneous structure of the filter cake, pore connectivity, and dewatering efficiency. Compared with the traditional two-dimensional theoretical model, this method underestimates the total porosity by 12 - 18%, emphasizing the necessity and effectiveness of three-dimensional analysis.

In order to solve the problems that the traditional flotation tailings ash detection mostly depends on the color of the surface slurry, the correlation is not high and it is susceptible to environmental interference, a new method for tailings ash detection based on robotic arm-assisted stratification is proposed and implemented. Firstly, the difference in settlement velocity between coal and gangue in the process of static and flow dumping was analyzed by using the principles of physical mechanics, so as to provide theoretical support for the stratification of coal gangue in tailings. Subsequently, a six-degree-of-freedom manipulator model was established based on the DH parameter method, and its kinematics and working space were simulated with the help of MATLAB Robotics Toolbox, which verified that the selected manipulator could reach and run smoothly in the space environment of the coal preparation plant. In order to achieve fast and efficient online monitoring, this paper further uses the TOPP-RA algorithm to plan the time-optimal trajectory of the robotic arm, which significantly shortens the operation cycle while satisfying the speed and acceleration constraints. During the experiment, the manipulator arm made the coal and gangue in the tailings obviously stratified through reasonable tilt angle and vibration action. Then, the image processing technology was used to extract the area proportion of coal and gangue after stratification, and compared it with the ash value obtained by the actual laboratory analysis. The results show that the Pearson correlation coefficient between coal gangue proportion and tailings ash can reach 0.42 under the conditions of multiple coal types and working conditions, which is significantly better than the traditional detection method based on the color of surface slurry. This study provides a feasible automation solution for the prediction of flotation tailings ash, and lays an important foundation for the intelligent construction and refined production control of subsequent coal preparation plants.

The mainstream models of explosion-proof mining vehicles undertake over 70% of the trackless auxiliary transportation tasks for personnel, materials, gangue, and equipment in coal mines. However, mining explo-sion-proof vehicles are typically designed for specific transportation tasks and must undergo reconfiguration and modification when changing their use. To address the common issues of process discontinuity, multiple transfer links, high labor ratio, and low level of intelligence in existing vehicles, this article designs and develops an adaptive rubber wheel transport trailer system. This system can adapt to various transportation modes such as medium thick coal seams, thin coal seam tunnels, and non-road conditions, and features the ability to quickly replace working devices. Based on the analysis of key technologies in coal mine underground operating conditions, this article proposes an adaptive control overall scheme utilizing a three-point lifting mechanism. To verify the effectiveness of the scheme, this paper uses MATLAB/Simulink to simulate the key components and conducts on-site tests on the trailer system. The simulation and experimental results demonstrate that the design scheme of the adaptive rubber wheel transport trailer meets the requirements of use. By establishing a standard platform and implementing convenient replacement technology for working devices, personnel, materials, and equipment can be transported without transfer, significantly enhancing handling efficiency and elevating the generalization and intelligence level of coal mine special chassis. This is of great significance for promoting the development of underground transportation technology in coal mines.

To address the accumulation and blockage issues in coal chute transportation, an optimized chute structure design method based on the biomimetic mechanism of the lotus leaf's hydrophobicity is proposed. First, the chute curve is calculated by applying the steepest descent line in conjunction with the overall height of the coal chute. Points of abrupt slope changes and delayed changes are identified using the gradient descent principle. The chute bottom plate parameters are derived from the linear equation, and a relevant physical model is established. Second, an optimized coal chute model is developed based on the micro-nano structure of the lotus leaf surface. Finally, a three-factor, three-level orthogonal experiment is conducted. The movement of coal particles is simulated using Fluent-Rocky DEM coupled simulation, and the optimal parameters of the optimized structure are determined through range analysis: When the pore diameter is 20 mm, the pore spacing is 100 mm, and the wind speed is 100 m/s, the material particles exhibit the highest flowability, with no accumulation or blockage observed. Additionally, finite element analysis was conducted on the optimized coal chute. The results indicate that under a flow rate pressure of 1500 t/h, no deformation occurs, and the structural strength meets the requirements for normal coal transportation.